Surface modified carbon black to simultaneously improve rolling resistance, wet traction, and wear resistance

ABSTRACT

Non-ASTM low hysteresis carbon blacks chemically treated, and surface coated with a compound comprising at least one amine group and at least one thiol group, and/or di- and/or polysulfidic linkage. When compared with a standard ASTM grade compound, the disclosed surface modified low hysteresis carbon black compound shows improved rolling resistance, wet traction, and DIN abrasion, comparable to silica compounds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication Ser. No. 63/143,563, filed Jan. 29, 2021 and entitled“Surface Modified Carbon Black to Improve Rolling Resistance, WetTraction, and Wear Resistance Simultaneously,” the disclosure of whichis hereby incorporated herein by reference in its entirety for purposesnot contrary to this disclosure.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

This disclosure relates to a surface modified carbon black compound. Thedisclosure also relates to a compound of low hysteresis surface treatedcarbon black in solution styrene-butadiene rubber (SSBR)/polybutadienerubber (BR) blend with simultaneously improved rolling resistance, wettraction, and wear resistance.

BACKGROUND OF DISCLOSURE

Rolling resistance, wet traction, and wear resistance are three majorproperties of importance for tire manufacturers, and form the “magictriangle” of these properties. With ASTM standard carbon blacks, it hasconventionally been impossible to improve all three properties at thesame time, and tire manufacturers thus typically utilize silica as afiller in their tread compound to significantly improve rollingresistance and wet traction with some improvement or no negative effecton wear resistance. Rubber tread compound comprises polymer, filler,curatives, and other ingredients; typical rubber compound ingredientsare listed in Table 3 hereinbelow.

Compounding with silica is, however, costly due to the abrasive natureof silica, which results in the need for costly machinery maintenanceand the use of expensive coupling agents to act as a bridge betweensilica and polymer. Compared to carbon black, silica is more difficultto process, has no advantage in dry traction, is nonconductive, and itis thus ultimately necessary to combine silica with carbon black.Additionally, although the use of silica can improve rolling resistanceand wet traction in certain rubber compounds, these advantages are notpresent in all rubber compounds, notably natural rubber used in trucktires.

The prior art discloses different strategies that have been attempted inorder to develop new specialty carbon blacks and/or modify ASTM gradecarbon blacks in order to produce compounds with similar properties tothose provided by silica compounds. These prior art strategies havemainly focused on increasing filler-polymer interactions and minimizingfiller-filler interactions by modifying carbon black, polymer and mixingprocedures.

To achieve these goals, the prior art approaches have used lowhysteresis carbon black, surface treated carbon black, carbonblack-silica dual phase fillers (see, for example, Eco black by CabotCorp.), and carbon black with modified surface microstructure (see, forexample, ECORAX® by Orion) in tread compounds. None of these strategieshas, however, simultaneously improved rolling resistance, wet traction,and wear resistance (the magic triangle parameters noted above) assilica alone does.

For example, low hysteresis carbon black has been shown to improvesolely the rolling resistance. Compared to corresponding ASTM gradecarbon black, low hysteresis carbon black has a wider aggregate sizedistribution, with a higher percentage of larger aggregates. When thecarbon black aggregate size distribution is narrow, it has a greatertendency to form stronger filler-filler networking in the rubbercompound. Therefore, using carbon black with widened aggregate sizedistribution generally decreases the filler-filler networking strength,while maintaining the same average strength of polymer-fillerinteractions. However, low hysteresis carbon black is not adequate forincreasing polymer-filler interactions to result in improvement ofrubber properties other than rolling resistance.

Other prior art has focused on studies on surface treatment of carbonblack; most such studies have focused on increasing polymer-fillerinteractions. Some have shown improvement of rolling resistance but notwith simultaneous improvement in the other properties of the magictriangle (i.e., wet traction and wear resistance). Althoughpolymer-filler interaction was increased, filler-filler networkingstrength was still predominant. Accordingly, the three rubber propertiesof the magic triangle were not shown to improve concurrently.

U.S. Pat. No. 2013/0046064 A1 discloses a process for the use of surfacetreated carbon black with a functionalized polymer that displayed animproved rolling resistance, wet traction, and wear resistancecomparable to silica. However, utilization of functionalized polymer inthe tire industry is cost prohibitive and, thus, impractical.

A need thus exists for compounds and methods for practically andsimultaneously improving rolling resistance, wet traction, and wearresistance.

BRIEF SUMMARY OF DISCLOSURE

Disclosed herein are embodiments of a compound of low hysteresis surfacetreated carbon black in solution SBR/BR blend (e.g., SSBR/BR), whichsimultaneously improve rolling resistance, wet traction and wearresistance, and, thus, address the shortfalls of conventional compoundsand methods.

Herein disclosed is a surface modified low hysteresis carbon black(SMLHCB) compound to simultaneously improve rolling resistance, wettraction, and wear resistance, the SMLHCB compound comprising: a lowhysteresis carbon black having a surface that has been modified to havea surface modifier attached thereto, wherein the surface modifiercomprises at least one amine group and at least one thiol group and/ordi- and/or polysulfidic linkage.

Also disclosed herein is a rubber compound comprising the SMLHCBcompound of this disclosure and a natural or synthetic polymer orpolymer blend. The natural or synthetic polymer or polymer blend cancomprise a solution styrene butadiene rubber (SBR) (SSBR)-polybutadienerubber (BR) blend.

Further provided herein is a method of producing a surface modified lowhysteresis carbon black (SMLHCB), the method comprising: treating asurface of a low hysteresis carbon black with from about 0.1 to about 50wt % of a surface modifier, wherein the surface modifier comprises atleast one amine group, to form the SMLHCB.

Additionally, herein disclosed is a method for enhanced crosslinking ofa surface modified low hysteresis carbon black (SMLHCB) into a polymerto create a rubber compound, the method comprising: mixing the SMLHCBwith the polymer at a temperature and a pressure to provide the SMLHCB,wherein the SMLHCB is a SMLHCB as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of various exemplary embodiments, referencewill now be made to the accompanying drawings in which:

FIG. 1 depicts embodiments of 5× optical images of embodiments of carbonblacks according to this disclosure; (a) depicts N234, (b) depictsST4-N234, and (c) depicts ST8-N234;

FIG. 2 depicts a TGA profile of cystine-treated, and untreated N234 asdisclosed according to embodiments of this disclosure;

FIG. 3 depicts a “magic triangle” comprising indexed rolling resistance(RR), wet traction (WT), and DIN abrasion (DIN) values for embodimentsof compounds according to this disclosure; and

FIG. 4 depicts a hysteresis plot of embodiments of compounds accordingto this disclosure.

DETAILED DESCRIPTION

The following discussion is directed to various exemplary embodiments ofthis disclosure. However, the embodiments disclosed herein should not beinterpreted, or otherwise utilized, as limiting the scope of thedisclosure, including the claims. In addition, one skilled in the artwill understand that the following description has broad application,and the discussion of any embodiment is meant only to be exemplary ofthat embodiment, and that the scope of this disclosure, including theclaims, is not limited to that embodiment.

The drawing figures are not necessarily to scale. Certain features andcomponents herein may be shown exaggerated in scale or in somewhatschematic form and some details of conventional elements may be omittedin interest of clarity and conciseness.

In the following discussion and in the claims, the terms “including” and“comprising” are used in an open-ended fashion, and thus should beinterpreted to mean “including, but not limited to . . . .” As usedherein, the term “about,” when used in conjunction with a percentage orother numerical amount, means plus or minus 10% of that percentage orother numerical amount. For example, the term “about 80%,” wouldencompass 80% plus or minus 8%. References cited herein are incorporatedin their entirety by such reference for purposes not contrary to thisdisclosure.

In embodiments the rubber compound formulation from U.S. Pat. No.5,227,425 can be utilized as the silica compound formulation hereinnoted as a standard for comparison.

SMLHCB

Disclosed herein are embodiments of a compound of a surface modified lowhysteresis carbon black (SMLHCB) (e.g., ST4-N234 (Compound C), ST4-LH11(Compound D), described in the Examples hereinbelow) in solution SBR(SSBR)-Polybutadiene (BR) blend (e.g., a 75/25 ratio of SSBR/BR).Utilization of the SMLHCB can, in embodiments, simultaneously improverolling resistance, wet traction, and wear resistance, comparable to theproperties obtained with silica as filler. Filler-filler networkingstrength is advantageously decreased using low hysteresis carbon blackand, at the same time, polymer-filler interactions are increased usingsurface treated carbon black. These effects improve the rubber treadcompound properties of interest simultaneously and thus address theabove noted shortfalls of conventional methods.

In embodiments, a surface modified low hysteresis carbon black (SMLHCB)compound of this disclosure can simultaneously improve rollingresistance, wet traction, and wear resistance. The SMLHCB compound cancomprise: a low hysteresis carbon black having a surface that has beenmodified to have a surface modifier attached thereto. The surfacemodifier can comprise at least one amine group and/or at least one thiolgroup and/or di- or polysulfidic linkage. Also provided herein is arubber compound comprising the SMLHCB compound of this disclosure and anatural or synthetic polymer or polymer blend.

In embodiments, a rubber compound of this disclosure comprises asolution SBR (SSBR)-Polybutadiene (BR) blend. For example, the rubbercompound can have a weight ratio of SSBR:BR in a range of from about100:0, 99.9:0.1; 75:25, 0.1:99.9, or 0:100, or in a range of from about100:0 to about 0:100, from about 99.9:0.1 to about 0.1:99.9, from about90:10 to about 10:90, or from about 80:20 to about 20:80.

In embodiments, the surface modifier of the SMLHCB compound of thisdisclosure comprises an amino acid. For example, in embodiments, theamino acid can comprise a naturally occurring amino acid; a modifiednatural amino acid; a synthetic amino acid; a dimer thereof; a polymerthereof; a salt thereof; or a combination thereof. By way of furtherexample, in embodiments, the amino acid comprises cysteine, cystine,homocysteine, homocystine, methionine, or a combination thereof.

In embodiments, the surface modifier comprises an amino acid having atleast one thiol group and/or or di- or polysulfidic linkage, and/or anorganic or inorganic compound containing at least one amine group, andat least one thiol group and/or di- or polysulfidic linkage. The surfacemodifier can, in embodiments, be chemically linked to the surface of thecarbon black (e.g., the surface of the low hysteresis carbon black) viasingle or multiple bonds. In embodiments, the surface modifier can bechemically linked to the surface by an amide or other bond formation,chemisorption, physisorption, or a combination thereof. In embodiments,the surface modifier can be linked to the surface by at least one of:van der Waals interactions with a porous three-dimensional graphitelattice of the low hysteresis carbon black, covalent and/or ionic orother non-valent interactions with active surface moieties of thesurface. Said active surface moieties can comprise oxygen, nitrogen,and/or sulfur on the surface.

In embodiments, the surface modifier comprises from about 0.1 to about50 wt %, from about 0.1 to about 30 wt %, from about 1.0 to about 16 wt%, or from about 3 to about 20 wt % of the surface modified carbon black(e.g., of the surface modified low hysteresis carbon black (SMLHCB)).

As noted above, the chemical surface treatment and/or modification ofthe carbon black can be effected via utilization of any naturallyoccurring amino acid; a modified natural amino acid, or a syntheticamino acid or salt form thereof; a dimer; or polymer, or a salt form ofany dimer or polymer formed by any amino acid compound disclosed herein.In embodiments, as noted above, the amino acid comprises at least onethiol group, and/or di- and/or polysulfidic linkage, or any organic orinorganic compound containing at least one amine group and at least onethiol group, and/or di- and/or polysulfidic linkage. In embodiments theamino acid(s) utilized as surface treatment compounds include cysteine,cystine, homocysteine, homocysteine, and/or methionine.

In embodiments, chemical compounds containing amine groups can bind tothe carbon black surface by reacting with strong acidic groups presenton the surface (See for example: Chemical Bonding ofTetraethylenepentamine to Nitric Acid-Oxidized Carbon Fibers: An XPS/ISSInvestigation, Steven D. Gardner, Chakravarthy S. K. Singamsetty, GuorenHe, and Charles U. Pittman, 51(5), 636, 1997).

In embodiments, the chemical compound utilized in the surface treatmentof the carbon black can be chemisorbed onto the carbon black surface viaamide bond formation by virtue of the reaction of an amine group of thechemical compound used in the surface treatment and strong acidic groupson the carbon black surface. In embodiments the surface treatmentchemical compound is an amino acid as disclosed herein, wherein theamino acid comprises at least one thiol group, and/or di- and/orpolysulfidic linkage.

In embodiments, a surface treatment chemical compound may comprise morethan one amine group, and thus can form multiple (e.g., a plurality of)bonds with the carbon black surface. In addition to the amide bondformation, the surface treatment chemical compound may adhere to thecarbon black surface by chemisorption or physisorption through at leastone of: van der Waals interactions with porous three-dimensionalgraphite lattice of carbon black, covalent and/or ionic or othernon-valent interactions with active species such as oxygen, nitrogen,etc. found on the carbon black surface.

In a further embodiment, the thiol group(s) present in the surfacetreatment chemical compound may form a chemical bond with polymerscontaining unsaturated bonds. The polysulfidic linkage in the surfacetreatment chemical compound can fracture during vulcanization and form achemical bond with unsaturated polymer. In embodiments, the surfacetreatment chemical compound can further react with elemental sulfur toform additional polysulfidic linkages between the filler and polymer.

The SMLHCB compound can have a widened aggregate size distribution witha higher percentage of larger aggregates than a standard ASTM gradecarbon black that is not low hysteresis.

In embodiments, the carbon black can be pretreated by oxidation prior tosurface treatment with surface treatment chemical compounds. Such anoxidative process can be performed to increase a number of acidic groupson the surface of carbon black available to react with an amine group ofthe surface treatment chemical compound. In embodiments, thepretreatment by oxidation of the carbon black may be performed bymethods such as, but not limited to, ozone treatment, heat treatment,plasma treatment, nitrogen oxides treatment, gaseous or aqueous hydrogenperoxide treatment, liquid nitric acid treatment, or a combinationthereof.

The surface of the low hysteresis carbon black can thus, in embodiments,be oxidized prior to surface modification of the low hysteresis carbonblack filler to produce the SMLHCB compound. For example, the surfacecan be oxidized by ozone treatment, heat treatment, plasma treatment,gaseous or aqueous hydrogen peroxide treatment, nitrogen oxidestreatment, liquid nitric acid treatment, or a combination thereof.

In embodiments, an aggregate size of the low hysteresis carbon blackfiller can be in a range of from about 0.005 to about 1.0 micrometers(μm), from about 0.01 to about 0.8 μm, or from about 0.02 to about 0.6μm. The SMLHCB can have a surface area in a range of from about 10 toabout 250 m²/g, from about 20 to about 200 m²/g, or from about 30 toabout 150 m²/g.

Method of Producing SMLHCB

Also disclosed herein is a method of producing a surface modified lowhysteresis carbon black (SMLHCB). In embodiments, the method comprises:treating a surface of a low hysteresis carbon black with from about 0.1to about 50 wt %, from about 0.1 to about 30 wt %, from about 1 to about16 wt %, or from about 3 to about 20 wt % of a surface modifier (asdescribed above) to form the SMLHCB. In embodiments, the surfacemodifier comprises at least one amine group. In embodiments, treatingthe surface can comprise treatment via an acid-base process. As notedabove, an aggregate size of the low hysteresis carbon black that istreated can be in a range of from about 0.005 to about 1.0 micrometers(μall), from about 0.01 to about 0.8 μm, or from about 0.02 to about 0.6μm. In embodiments, the SMLHCB can have a surface area (e.g., a BETsurface area) in a range of from about 10 to about 250 m²/g, from about20 to about 200 m²/g, or from about 30 to about 150 m²/g. A number ofacidic groups on the surface can be increased before or during thetreating of the surface. Accordingly, in embodiments, the method canfurther comprise using the low hysteresis carbon black (LHCB) directlywithout acid treatment or activating the surface and/or treating thesurface with an acid to facilitate the treating of the surface with thesurface modifier. The method can comprise utilizing the surface modifierdirectly without solubilizing same in basic solution or can includeincreasing a solubility of the surface modifier in liquid medium (e.g.,water) by pre-treating the surface modifier with an inorganic and/ororganic base (e.g., in pure form, in modified form, and/or in asolvent).

Method of Enhancing Crosslinking of SMLHCB

Also provided herein is a method for enhanced crosslinking of a surfacemodified low hysteresis carbon black (SMLHCB) into a polymer to create arubber compound. In embodiments, the method can comprise: mixing theSMLHCB with the polymer at a temperature and a pressure (e.g., atemperature of about 165, 120, or 100° C., a pressure of about 80, 70 or60 psi); reacting the SMLHCB with unsaturated bonds of said polymer withthiol group(s), and/or with disulfide and/or polysulfide linkage(s) onthe surface of the SMLHCB; and curing to form the rubber compound.Curing can comprise heating the rubber compound (e.g., at 145° C.) underpressure (e.g., about 35,000 psi pressure, for example, using alaboratory press) for a specified time period, for example as determinedby rheometer (e.g., Moving Die Rheometer: MDR)), wherein the SMLHCB is aSMLHCB as described hereinabove.

Features and Potential Advantages

The rubber compound produced as described hereinabove can comprise areduced filler-filler networking, an increased amount of polymer-fillerinteractions, or both the reduced filler-filler networking and theincreased amount of polymer-filler interactions, relative to anotherwise same rubber compound produced with a standard ASTM gradecarbon black (e.g., that is not low hysteresis).

The rubber compound as produced and described herein can simultaneouslyexhibit improved rolling resistance, wet traction, and wear resistancerelative to an otherwise same rubber compound produced with a standardASTM grade carbon black (e.g., that is not low hysteresis and/or surfacemodified).

In embodiments the surface of carbon black (CB) can be modified asdescribed hereinabove to: (a) improve carbon black-polymer (CB-P)interactions and/or to: (b) eliminate the need for utilization of acoupling agent in tread compounds. In embodiments the surface treatedcarbon blacks produced and disclosed as described herein can be utilizedto prepare a tread compound, the final product properties of which arecomparable to those of conventional tread compounds comprising thesilica compound utilized as an industrial standard.

EXAMPLES Example 1: Preparation of Surface Treated Carbon Black

In embodiments, as disclosed herein, and in order to improve compoundproperties, a carbon black surface can be coated with amino acidpolysulfides utilizing a coat-mix procedure (Luhleich, et al. Carbon,Vol. 35, pp. 95-102, 1997), based on either a solvent or acid-baseprocess.

As a non-limiting example, the process described herein can utilizecystine (Formula 1):

The water solubility of cystine is low, and about 0.1 g/L. Conversion ofcystine to the anionic form (sodium salt) can be attained in basic media(pH>8), where the acid groups —COOH become —COO⁻. Very high watersolubility can be achieved, allowing equilibrium coverage of theavailable carbon black surface in minimal time with lower volumes ofwater.

The reaction of cystine with base (i.e. NaOH) to create the solubleanionic form is stoichiometric, so a known amount of base can be added.To neutralize the cystine salt on the carbon black surface, the carbonblack can first be acidified with the equivalent amount of acid (such asbut not limited to hydrochloric acid (HCl)) in deionized water. Thecoating can be performed, as in this Example 1, by the slow addition ofbasic cystine solution to acidified carbon black suspension withconstant stirring, while monitoring the pH of the batch.

Upon completion of cystine addition, the carbon black (CB) settled in auniform layer and the NaCl/water (pH˜7.5) supernatant layer wasdecanted. The carbon can then be washed and dried. For example, in thisExample 1, the carbon was washed, e.g., 3 to 4 times, with deionizedwater, to remove traces of NaCl. The wet carbon/cystine slurry was thenair dried, followed by oven drying for 2 hours at 140° C.

Cys-H+NaOH(aq)→Cys⁻Na⁺+H₂O pH>8

CB+HCl(aq)→CBH⁺+Cl⁻pH<2

CBH⁺+Cl⁻+Cys⁻Na⁺→CB-Cys-H+NaCl(aq)pH˜7.5

Example 2: Characterization of Carbon Black

Microscopic images of surface treated carbon black provide an idea ofuniform coating. ASTM grade N234 carbon black was used as standardcarbon black in a model tread compound. For this microscopiccharacterization study of Example 2, carbon black was treated withvarious quantities of cystine. When sufficient surface functional groupsare present in the carbon black to bind with cystine, and the cystinecontent exceeds the surface area capacity for molecular coverage, whitecolored cystine crystal islands can be seen by microscope. FIG. 1 showsoptical microscope images of untreated N234 in (a), treated N234 with 4weight percent (wt %) cystine (ST4-N234) in (b) and treated N234 with 8wt % cystine (ST8-N234) in (c). The plots of FIG. 1 suggest that 4 wt %of cystine can be uniformly coated, but 8 wt % of cystine resulted insome excess which was physiosorbed on the surface on N234, creatingsmall cystine crystal islands. FIG. 1, panel (c) shows these whitecystine crystals.

Thermal gravimetric analysis (TGA) suggested that attachment of cystinebeyond physisorption had occurred. The TGA profile of pure cystine showsmass loss at approximately 250° C.; carbon black mass loss associatedwith carbon black burn-off appears at approximately 600° C., as seen inFIG. 2, which depicts a TGA profile of cystine-treated, and untreatedN234. The TGA profile of untreated N234 does not show any mass loss at250° C. The mass loss for ST4-N234 at this temperature is small,suggesting that the majority of the cystine has been chemisorbed.Compared to ST4-N234, ST8-N234 showed a larger mass loss at 250° C.,which suggests more physisorption of cystine.

The strong acidic groups on the carbon black surface are key functionalgroups for chemisorption of surface treatment chemical compound viareaction with amine groups. The number of carboxylic acidic groups onthe carbon black samples can be determined by treating the carbon blackwith sodium bicarbonate followed by back titration procedure (seeExample 4 and Table 2 hereinbelow; see also, for example: BoehmTitration Revisited (Part I): Practical Aspects for Achieving a HighPrecision in Quantifying Oxygen-Containing Surface Groups on CarbonMaterials, Jan Schönherr, Johannes R. Buchheim, Peter Scholz, andPhilipp Adelhelm, C, 4, 21, 2018).

In this Example, during the surface treating process, the carbon blackwas acidified before reacting with the surface treatment chemicalcompound. This acidification caused the hydrolysis of lactonic groups onthe carbon black surface, thus increasing the number of carboxylic acidgroups. The anhydride groups present on the carbon black surface canalso hydrolyze in aqueous medium, yielding carboxylic acid groups.Therefore, pre-modification/activation, as described hereinabove, of thesurface can be performed before the reaction with the surface treatmentcompound(s). The data of Table 2, discussed hereinbelow, furtherconfirmed the modification of the surface with the acidification step.The number of lactonic groups was determined by treating the carbonblack with sodium carbonate followed by back titration procedure.

Surface treating changes the basic properties of carbon black (surfacearea and structure). Table 1 compares these properties for untreated andtreated N234 and LH11. Surface treatment decreases surface area andstructure and makes the carbon black more dense,

TABLE 1 Analytical Properties of Treated and Untreated Carbon BlackProperty N234 ST4-N234 LH11 ST4-LH11 NSA, m²/g 119.7 114.3 118.0 113.4STSA, m²/g 110.9 110.0 110.5 108.3 OAN, mL/100 g 128.0 126.9 136.2 131.1COAN, 101.5 100.4 108.7 106.8 mL/100 g Density, lb/ft³ 20.4 20.7 19.419.8 NSA: nitrogen surface area; STSA: statistical thickness surfacearea; OAN: oil absorption number; COAN: oil absorption number ofcompressed carbon black.

The number of carboxylic acidic groups on the carbon black samples wasdetermined by treating the carbon black with sodium bicarbonate followedby back titration procedure, and the results are tabulated in Table 2.

TABLE 2 Number of Carboxylic and Lactonic Groups Present in HCl Treatedand Untreated Carbon Black Carboxylic Acid Lactonic Groups Groups Sample(μmol/g) (μmol/g) N234 7.69 52.62 HCl treated N234 9.97 10.74 LH11 5.0868.46 HC1 treated LH11 9.30 12.08

Example 3: Rubber Compounding

As disclosed hereinabove, three major properties (the magic triangleproperties) for tire performance are rolling resistance, wet traction,and wear resistance. In a laboratory set-up, these properties generallycorrelate with tan δ values at 70 and 0° C. and DIN abrasionrespectively. High tan δ at 0° C., low tan δ at 70° C., and low DINabrasion are generally desirable.

To study the effects of the carbon black surface treatment of thisdisclosure on rubber compound properties, a compound recipe from U.S.Pat. No. 5,227,425 was utilized as a model compound. Table 3 lists theingredients utilized in each compound.

TABLE 3 Mixing Recipes A B C D E Ingredients (N234) (LH11) (ST4-N234)(ST4-LH11) (Silica) SSBR¹/BR² 75/25 75/25 75/25 75/25 75/25 N234 72 0 00 0 LH11 0 72 0 0 0 ST4-N234 0 0 72 0 0 ST4-LH11 0 0 0 72 0Silica-Particulate 0 0 0 0 80 X50S 0 0 0 0 12.5 Aromatic Oil 32.5 32.532.5 32.5 32.5 (SUNDEX ® 8125) ZnO 2.5 2.5 2.5 2.5 2.5 Stearic Acid 1 11 1 1 Paraffin Wax 1.5 1.5 1.5 1.5 1.5 (BOWAX ™ 615) Antioxidant 2 2 2 22 (SANTOFLEX ™ 13) Sulfur 2 2 2 2 1.4 SANTOCURE ® NS (TBBS) 1.5 1.5 1.51.5 0 CBS—Sulfenamid Accelerator 0 0 0 0 1.7 DPG—Diphenylguanidine 0 0 00 2.0 Accelerator ¹Solution Polymerization Styrene-Butadiene Rubber²PolyButadiene

To achieve the best dispersion, a 3-pass mixing process was used tomaximize the compound M300/M100 modulus ratio (force ratio at 300%elongation to 100% elongation) which is an indication of properdispersion.

Example 4: Results and Discussion

Compound A was prepared using standard ASTM grade N234 carbon black.Compound B was comparable to compound A, except that low hysteresiscarbon black (LH11) was used in the compound. Compounds C and D arecorresponding compounds to A and B, where surface treated carbon blackswere utilized in the compounds. Compound E was a model tread compoundwith silica as the filler instead of carbon black.

To evaluate tire tread compound performance properties, dynamicmechanical properties of compounds in −20 to 80° C. temperature range,along with DIN abrasion of compounds, were tested. Table 4 shows theindexed values for these properties; the higher the index, the betterthe property. FIG. 3 depicts the “magic triangle” comprising indexedrolling resistance (RR), wet traction (WT), and DIN abrasion (DIN)values for embodiments of compounds A-E of Examples 3-4.

TABLE 4 Indexed Tire Performance Properties A B C D E Property (N234)(LH11) (ST4-N234) (ST4-LH11) (Silica) M300/M100 4.8 4.8 4.4 4.3 5.0 DINAbrasion Resistance Index 100 103 97 106 120 Wet Traction (tanδ @0° C.)Index 100 98 100 113 137 Rolling Resistance (tanδ @70° C.) 100 103 106132 154

FIG. 4, which depicts hysteresis plots of compounds according to thisdisclosure, shows that the hysteresis plot of the compound comprisingLH11 (Compound B) has shifted down compared to that of the compoundcomprising standard N234 carbon black (Compound A), confirming that LH11is a low hysteresis carbon black. This means that the LH11 compound(Compound B) compared to N234 compound (Compound A) exhibits betterrolling resistance and worse wet traction.

When the surface of standard N234 (Compound A) was modified chemicallyby cystine (ST4-N234 (Compound C)), rolling resistance was improved by6% compared to standard N234 compound (Compound A). Improvement inrolling resistance by ST4-N234 compound (Compound C) and silica(Compound E) were 3% and 54% respectively and, hence, improvement byST4-N234 compound (Compound C) was about 11% of the improvement bysilica (Compound E). This treatment did not change the wet traction,however, there was a 3% negative effect in DIN abrasion for a ST4-N234compound (Compound C) while a silica compound (Compound E) had 37%improvement in wet traction and 20% improvement in DIN abrasion.

When the surface of a low hysteresis carbon black (LH11) was modifiedchemically by cystine (ST4-LH11 (Compound D)), rolling resistance wasimproved by 32%. This was about a 60% improvement in rolling resistanceas compared to when silica was used as filler (Compound E). In addition,a ST4-LH11 compound (Compound D) had 13% improvement in wet traction and6% improvement in DIN abrasion. These improvements were about 35% and30% of the improvements in wet traction and DIN abrasion respectivelywhen silica was used as filler (Compound E).

In direct comparison, the surface treatment of low hysteresis carbonblack as disclosed herein significantly improves rolling resistance, wettraction, and DIN abrasion of rubber compound, such that improvement ofall three properties in the “magic triangle” are comparable to silicacompounds, but without the negative properties associated therewith.

ADDITIONAL DISCLOSURE

The following are non-limiting, specific embodiments in accordance withthe present disclosure:

A first embodiment comprises: a surface modified low hysteresis carbonblack (SMLHCB) compound to simultaneously improve rolling resistance,wet traction, and wear resistance, the SMLHCB compound comprising: a lowhysteresis carbon black having a surface that has been modified to havea surface modifier attached thereto, wherein the surface modifiercomprises at least one amine group and at least one thiol group or di-or polysulfidic linkage.

In a second embodiment, a rubber compound comprises the SMLHCB compoundof the first embodiment and a natural and/or synthetic polymer and/orpolymer blend.

A third embodiment can include the rubber compound of the secondembodiment, comprising a solution styrene butadiene rubber (SBR)(SSBR)-Polybutadiene (BR) blend.

A fourth embodiment can include the rubber compound of the thirdembodiment, comprising a weight ratio of SSBR:BR of about 100:0, 75:25,or 0:100, or in a range of from about 100:0 to about 0:100, from about90:10 to about 10:90, or from about 80:20 to about 20:80.

A fifth embodiment can include the SMLHCB compound of the firstembodiment, wherein the surface modifier comprises an amino acid.

A sixth embodiment can include the SMLHCB compound of the fifthembodiment, wherein the amino acid comprises a naturally occurring aminoacid; a modified natural amino acid; a synthetic amino acid; a dimerthereof; a polymer thereof; a salt thereof; or a combination thereof.

A seventh embodiment can include the SMLHCB compound of any of the fifthand sixth embodiments, wherein the amino acid comprises cysteine,cystine, homocysteine, homocystine, methionine, or a combinationthereof.

An eighth embodiment can include the SMLHCB compound of any one of thefirst and fifth to seventh embodiments, wherein the surface modifiercomprises an amino acid having at least one thiol group, and/or di-and/or polysulfidic linkage, or an organic and/or inorganic compoundcontaining at least one amine group, and at least one thiol group,and/or di- and/or polysulfidic linkage.

A ninth embodiment can include the SMLHCB compound of any of the priorembodiments, wherein the surface modifier is chemically linked to thesurface via single or multiple bonds.

A tenth embodiment can include the SMLHCB compound of any of the priorembodiments, wherein the surface modifier is chemically linked to thesurface by an amide or other bond formation, chemisorption, and/orphysisorption.

An eleventh embodiment can include the SMLHCB compound of any of theprior embodiments, wherein the surface modifier is linked to the surfaceby at least one of: van der Waals interactions with a porousthree-dimensional graphite lattice of the low hysteresis carbon black,covalent and/or ionic or other non-valent interactions with activesurface moieties of the surface.

A twelfth embodiment can include the SMLHCB compound of any of the priorembodiments, wherein said active surface moieties comprise oxygen,nitrogen, and/or sulfur on the surface.

A thirteenth embodiment can include the SMLHCB compound of any of theprior embodiments, wherein the surface modifier comprises from about 0.1to about 50 wt %, from about 0.1 to about 30 wt %, from about 1.0 toabout 16 wt %, or from about 3 to about 20 wt % of the carbon black.

A fourteenth embodiment can include the SMLHCB compound of any of theprior embodiments, wherein said SMLHCB compound has a widened aggregatesize distribution with higher percentage of larger aggregates than astandard ASTM grade carbon black that is not low hysteresis.

A fifteenth embodiment can include the SMLHCB compound of any of theprior embodiments, wherein said surface was oxidized prior to surfacemodification of the low hysteresis carbon black filler to produce theSMLHCB compound.

A sixteenth embodiment can include the SMLHCB compound of any of theprior embodiments, wherein the surface was oxidized by ozone treatment,heat treatment, plasma treatment, gaseous or aqueous hydrogen peroxidetreatment, nitrogen oxides treatment, liquid nitric acid treatment, or acombination thereof.

A seventeenth embodiment can include the SMLHCB compound of any of theprior embodiments, wherein an aggregate size of the low hysteresiscarbon black filler is in a range of from about 0.005 to about 1.0micrometers (μm), from about 0.01 to about 0.8 μm, or from about 0.02 toabout 0.6 μm.

An eighteenth embodiment can include the SMLHCB compound of any of theprior embodiments, wherein the SMLHCB has a surface area in a range offrom about 10 to about 250 m²/g, from about 20 to about 200 m²/g, orfrom about 30 to about 150 m²/g.

In a nineteenth embodiment, a method of producing a surface modified lowhysteresis carbon black (SMLHCB) comprises: treating a surface of a lowhysteresis carbon black with from about 0.1 to about 50 wt %, from about0.1 to about 30 wt %, from about 1 to about 16 wt %, or from about 3 toabout 20 wt % of the surface modifier, wherein the surface modifiercomprises at least one amine group, to form the SMLHCB.

A twentieth embodiment can include the method of the nineteenthembodiment, wherein treating comprises treatment via an acid-baseprocess.

A twenty first embodiment can include the method of the nineteenth ortwentieth embodiment, wherein an aggregate size of the low hysteresiscarbon black is in a range of from about 0.005 to about 1.0 micrometers(μm), from about 0.01 to about 0.8 μm, or from about 0.02 to about 0.6μm.

A twenty second embodiment can include the method of any one of thenineteenth to twenty first embodiments, wherein the SMLHCB has a surfacearea (e.g., a BET surface area) in a range of from about 10 to about 250m²/g, from about 20 to about 200 m²/g, or from about 30 to about 150m²/g.

A twenty third embodiment can include the method of any one of thenineteenth to twenty second embodiments, wherein a number of acidicgroups on the surface is increased before or during the treating of thesurface.

A twenty fourth embodiment can include the method of any one of thenineteenth to twenty third embodiments, further comprising the using ofLHCB directly without acid treatment or activating the surface and/ortreating the surface with an acid to facilitate the treating of thesurface with the surface modifier.

A twenty fifth embodiment can include the method of any one of thenineteenth to twenty fourth embodiments, further comprising the using ofsurface modifier directly without solubilizing in basic solution orincreasing solubility of the surface modifier in liquid medium (e.g.,water) by pre-treating with an inorganic or organic base (e.g., in pureform, in modified form, and/or in a solvent).

In a twenty sixth embodiment, a method for enhanced crosslinking of asurface modified low hysteresis carbon black (SMLHCB) into a polymer tocreate a rubber compound comprises: mixing the SMLHCB with the polymerat a temperature and a pressure (e.g., a temperature of about 165, 120,or 100° C., a pressure of about 80, 70 or 60 psi); reacting the SMLHCBwith unsaturated bonds of said polymer with thiol group(s), and/ordisulfide and/or polysulfide linkage(s) on the surface of the SMLHCB;and curing to form the rubber compound (e.g., wherein curing comprisesheating the rubber compound (e.g., at 145° C.) under pressure (e.g.,about 35,000 psi pressure, for example, using a laboratory press) for aspecified time period determined by rheometer (e.g., Moving DieRheometer: MDR)), wherein the SMLHCB is a SMLHCB of any of the priorembodiments.

A twenty seventh embodiment can include the method of the twenty sixthembodiment, wherein the rubber compound comprises a reducedfiller-filler networking, an increased polymer-filler interactions, orboth reduced filler-filler networking and increased polymer-fillerinteractions, relative to an otherwise same rubber compound producedwith a standard ASTM grade carbon black that is not low hysteresis.

A twenty eighth embodiment can include the method of the twenty sixth ortwenty seventh embodiment, wherein said rubber compound simultaneouslyexhibits improved rolling resistance, wet traction, and wear resistancerelative to an otherwise same rubber compound produced with a standardASTM grade carbon black that is not low hysteresis.

While embodiments have been shown and described, modifications thereofcan be made by one skilled in the art without departing from the spiritand teachings of this disclosure. The embodiments described herein areexemplary only, and are not intended to be limiting. Many variations andmodifications of the embodiments disclosed herein are possible and arewithin the scope of this disclosure. Where numerical ranges orlimitations are expressly stated, such express ranges or limitationsshould be understood to include iterative ranges or limitations of likemagnitude falling within the expressly stated ranges or limitations(e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numericalrange with a lower limit, Rl, and an upper limit, Ru, is disclosed, anynumber falling within the range is specifically disclosed. Inparticular, the following numbers within the range are specificallydisclosed: R=Rl+k*(Ru−RI), wherein k is a variable ranging from 1percent to 100 percent with a 1 percent increment, i.e., k is 1 percent,2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98percent, 99 percent, or 100 percent. Moreover, any numerical rangedefined by two R numbers as defined in the above is also specificallydisclosed. Use of the term “optionally” with respect to any element of aclaim is intended to mean that the subject element is required, oralternatively, is not required. Both alternatives are intended to bewithin the scope of the claim. Use of broader terms such as comprises,includes, having, etc. should be understood to provide support fornarrower terms such as consisting of, consisting essentially of,comprised substantially of, etc.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present disclosure. Thus, the claims are a further description andare an addition to the embodiments of the present disclosure. Thediscussion of a reference herein is not an admission that it is priorart, especially any reference that may have a publication date after thepriority date of this application. The disclosures of all patents,patent applications, and publications cited herein are herebyincorporated by reference, to the extent that they provide exemplary,procedural, or other details supplementary to those set forth herein.

What is claimed is:
 1. A surface modified low hysteresis carbon black(SMLHCB) compound to simultaneously improve rolling resistance, wettraction, and wear resistance, the SMLHCB compound comprising: a lowhysteresis carbon black having a surface that has been modified to havea surface modifier attached thereto, wherein the surface modifiercomprises at least one amine group and at least one thiol group and/ordi- and/or polysulfidic linkage.
 2. A rubber compound comprising theSMLHCB compound of claim 1 and a natural or synthetic polymer or polymerblend.
 3. The rubber compound of claim 2, comprising a solution styrenebutadiene rubber (SBR) (SSBR)-polybutadiene rubber (BR) blend.
 4. Therubber compound of claim 3, comprising a weight ratio of SSBR:BR ofabout 100:0, or in a range of from about 100:0 to about 0:100.
 5. TheSMLHCB compound of claim 1, wherein the surface modifier comprises anamino acid.
 6. The SMLHCB compound of claim 5, wherein the amino acidcomprises a naturally occurring amino acid; a modified natural aminoacid; a synthetic amino acid; a dimer thereof; a polymer thereof; a saltthereof; or a combination thereof.
 7. The SMLHCB compound of claim 5,wherein the amino acid comprises cysteine, cystine, homocysteine,homocystine, methionine, or a combination thereof.
 8. The SMLHCBcompound of claim 1, wherein the surface modifier comprises an aminoacid having at least one thiol group, and/or di- and/or polysulfidiclinkage, or an organic and/or inorganic compound containing at least oneamine group, and at least one thiol group and/or di- and/or polysulfidiclinkage.
 9. The SMLHCB compound of claim 1, wherein the surface modifieris chemically linked to the surface via single or multiple bonds. 10.The SMLHCB compound of claim 9, wherein the surface modifier ischemically linked to the surface by an amide or other bond formation,chemisorption, and/or physisorption.
 11. The SMLHCB compound of claim 9,wherein the surface modifier is linked to the surface by at least oneof: van der Waals interactions with a porous three-dimensional graphitelattice of the low hysteresis carbon black, covalent and/or ionic orother non-valent interactions with active surface moieties of thesurface.
 12. The SMLHCB compound of claim 11, wherein said activesurface moieties comprise oxygen, nitrogen, and/or sulfur on thesurface.
 13. The SMLHCB compound of claim 1, wherein the surfacemodifier comprises from about 0.1 to about 50 wt % of the carbon black.14. The SMLHCB compound of claim 1, wherein said SMLHCB compound has awidened aggregate size distribution with higher percentage of largeraggregates than a standard ASTM grade carbon black that is not lowhysteresis.
 15. The SMLHCB compound of claim 1, wherein said surface wasoxidized prior to surface modification of the low hysteresis carbonblack filler to produce the SMLHCB compound.
 16. The SMLHCB compound ofclaim 15, wherein the surface was oxidized by ozone treatment, heattreatment, plasma treatment, gaseous or aqueous hydrogen peroxidetreatment, nitrogen oxides treatment, liquid nitric acid treatment, or acombination thereof.
 17. The SMLHCB compound of claim 1, wherein anaggregate size of the low hysteresis carbon black filler is in a rangeof from about 0.005 to about 1.0 micrometers (μm).
 18. The SMLHCBcompound of claim 1, wherein the SMLHCB has a surface area in a range offrom about 10 to about 250 m²/g.
 19. A method of producing a surfacemodified low hysteresis carbon black (SMLHCB), the method comprising:treating a surface of a low hysteresis carbon black with from about 0.1to about 50 wt % of a surface modifier, wherein the surface modifiercomprises at least one amine group, to form the SMLHCB.
 20. The methodof claim 19, wherein treating comprises treatment via an acid-baseprocess.
 21. The method of claim 19, wherein an aggregate size of thelow hysteresis carbon black is in a range of from about 0.005 to about1.0 micrometers (μall).
 22. The method of claim 19, wherein the SMLHCBhas a surface area in a range of from about 10 to about 250 m²/g. 23.The method of claim 19, wherein a number of acidic groups on the surfaceis increased before or during the treating of the surface.
 24. Themethod of claim 19 further comprising the using of LHCB directly withoutacid treatment or activating the surface and/or treating the surfacewith an acid to facilitate the treating of the surface with the surfacemodifier.
 25. The method of claim 19 further comprising the using ofsurface modifier directly without solubilizing in basic solution, orincreasing solubility of the surface modifier in liquid medium bypre-treating with an inorganic or organic base.
 26. A method forenhanced crosslinking of a surface modified low hysteresis carbon black(SMLHCB) into a polymer to create a rubber compound, the methodcomprising: mixing the SMLHCB with the polymer at a temperature and apressure, wherein the SMLHCB is a SMLHCB of claim
 1. 27. The method ofclaim 26, wherein the rubber compound comprises a reduced filler-fillernetworking, an increased amount of polymer-filler interactions, or boththe reduced filler-filler networking and the increased amount ofpolymer-filler interactions, relative to an otherwise same rubbercompound produced with a standard ASTM grade carbon black that is notlow hysteresis.
 28. The method of claim 26, wherein said rubber compoundsimultaneously exhibits improved rolling resistance, wet traction, andwear resistance relative to an otherwise same rubber compound producedwith a standard ASTM grade carbon black that is not low hysteresis.